The integration of lighting areas in interior trim pieces of motor vehicles currently finds ever increasing use. A line lighting, i.e. the formation of a light line, such as a homogenous line of light, which extends over one or more interior trim pieces, in particular, is of particular interest.
For example, German Patent Document DE 10 2013 200 441 B3 describes a motor vehicle lighting device having a light guide, into which light can be fed by way of a light source. The light guide has a light-exit face which extends along a principal direction. Moreover, the light guide has a deflection face from which light that is incident by way of total-internal reflection is reflected toward the exit face.
German Patent Document DE 10 2013 213 523 A1 discloses a diffusing screen with a receiving portion for a line-shaped light guide, an emission portion extending parallel to the receiving portion for emitting light from the diffusing screen, and a connecting portion which connects the receiving portion with the emission portion. The diffusing screen consists of a transparent material such that light emitted by the line-shaped line guide can be received by the receiving portion and guided in the direction of the emission portion. In the emission portion, the light can leave the diffusing screen and radiate into the interior of the vehicle.
However, a problem regularly arising in the related art is that light inhomogeneity occurs at the boundary regions of the line lighting, i.e. at opposing longitudinal ends of the light line. This may be due, for example, to the fact that light from the light sources is reflected at the end sides of the light guide, which forms the light line, and consequently is superposed on the visible light guide side. Since this light superposition only occurs in the regions of the end sides and, as a rule, it does not occur over the remaining length of the light guide, an inhomogeneity may consequently occur in the light image.